As you probably know by now, G-Man has a blog (yay!).

Now that I've been noticed, I have started to get a bit of comment spam.  Since spam is a hobby of mine I've decided to categorize the top five types of comment spammers
  1. Sex for Fantasy - These are the guys who live in a fantasy world where everyone who sees their comments are going to click on the link.  They use all sorts of entertaining sexual words that are very easy to spot.  Their latest trick is to use a normal sentence like this and throw in a couple (or more) words that relate to the topic they're spamming.
  2. Now you see it, now you don't - These guys are a bit trickier.  If you don't spot them from the horrible text they use in their comments, you'll easily spot them by their 404 pages when you follow the links to the page they're promoting.  Why would they have a page like that?  Well, they're hoping you'll think the page is temporarily down while they actually are cloaking and provide real content to the search engines.
  3. Bold Spammers - These jokers still go with the old outdated theory that bolding text actually helps.  So they'll throw their keyword in the comment and bold it.  Nothing much to see here other than a couple of words that are bolded.  For those of you who are about to contest that, I've got a site that will be out soon with lots of very fascinating statistically based information on what the search engines like and don't like. 
  4. Foreign Language Spammer - If these guys did not put their keywords in bold at the top of their comments, they would be a bit harder to spot.  They'll usually throw their keywords in and then have some random foreign language spam on the page as well.  It helps them rank on the foreign language search engine as well as the English version.
  5. To the Point - Keyword followed by link.  Nothing to see here, move along :)
Those are the top five types of comment spammers that I see on a day to day basis.  Do you have any additions?

G-Man